Hot gas machine and control device for varying the power thereof

ABSTRACT

A hot-gas engine with a power control device comprising a compressor having an inlet selectively connectable either to the engine&#39;&#39;s working space outlet or to a working fluid storage container, while the compressor&#39;&#39;s outlet is selectively connectable either to the working space inlet or to the storage container.

United States Patent Abrahams Nov. 25, 1975 HOT GAS MACHINE AND CONTROL [56] References Cited DEVICE FOR VARYING THE POWER UNITED STATES PATENTS THEREOF 2,992,536 7/l96l Camahan 60/521 X [75] Inventor: Jacobus Hubertus Abrahams, 3,546,877 12/1970 Beukering et a1 60/521 X Eindhoven, Netherlands [73] Assignee: U.S. Philips Corporation, New Primary EXami' 1er"Manin Schwadron York, Asszstant Examiner-+1. Burks, Sr,

Attorney, Agent, or Firm-Frank R. Trifari; J. David May 3, Dainow [21] Appl. No.: 466,711

' 7] ABSTRACT [30] Foreign Application Priority Data A hot-gas engine with a power control device compris- May 21, 1973 Netherlands 7307041 ing a compreSsor having an inlet Selectively connectable either to the engines working space outlet or to a 52 U.S. c1. 60/521 Working fluid Storage Container, While the compres- 51 1m. 01. F01B 29/10 SOYS Outlet is Selectively conflectable either the [58] Field of Search 60/517, 527, 522, 524, working Space inlet or to the Storage Container- 60/52l 3 Claims, 5 Drawing Figures U.S. Patent N0v.25, 1975 Sheet10f2 3,921,401

Fig.1

U.S. Patent Nov. 25, 1975 Sheet 2 of2 3,921,401

HOT GAS MACHINE AND CONTROL DEVICE FOR VARYING THE POWER THEREOF BACKGROUND OF THE INVENTION The invention relates to a hot-gas reciprocating apparatus provided with a device for controlling the amount by weight of working fluid in a working space of the apparatus. Known devices of this type comprise a storage container for working fluid and a compressor for said fluid, with the storage container being connectable via a first conduit to an outlet of the working space, which outlet includes a first non-return valve, and via a second conduit to an inlet of the working space, which inlet includes a second non-return valve.

The term hot-gas reciprocating apparatus is to be understood herein to mean hot-gas reciprocating engines, cold-gas refrigerators and heat pumps. In the working spaces of these apparatus the working fluid is compressed, when it is contained mainly in a part of the working space, that is the compression space then the fluid is transferred via a regenerator to the expansion space where it is expanded, and finally it is returned via theregenerator to the compression space, so completing the cycle. The compression and expansion spaces have different mean temperatures in operation.

By means of the device for controlling the amount by weight of the working fluid in the working space of the hot-gas reciprocating apparatus, the power thereof can be varied dueto variation of the mean pressure level of the working fluid in the working space.

In hot-gas reciprocating apparatus described in US. Pat. Nos. 3,372,539 and 3,546,877, working fluid is withdrawn from the working space'via the first conduit and pressed into the storage container, which is constructed as a high-pressure container, by an external compressor included in this conduit. Working fluid is delivered to the working space from the high-pressure storage container via the second conduit by opening a valve included. in this conduit.

Instead of being external thecompressor may be located in the apparatus. In this case the internal compressor mayform an integral part of the apparatus, as is described in Netherlands Patent Application No.

However a disadvantage of this known apparatus is that a compressor having a high compression ratio is required to press working fluid into the storage container at a high pressure.

High compression ratios give rise to high compres- 'sion temperatures of the working fluid. In addition, in

hot-gas reciprocating engines the working fluid sucked by the compressor from the working space, is already at a comparatively high temperature, which also contributes to a high final compression temperature. These conditions adversely affect the useful life of the com pressor, in particular the useful life of the seals, which usually are made of a synthetic material, and of the inlet and outlet valves.

This disadvantage is avoided in the apparatus proposed in Netherlands Patent Application No. 71.16.550, wherein the compressor is connected in the second conduit instead of in the first one and pumps working fluid from the storage container to the working space of the apparatus instead of in the opposite direction.

When the pressure level in the apparatus is to be reduced. the first conduit is opened and working fluid LII flows to the storage container, which in this embodiment is a low-pressure storage container. Thus the compressor in the second conduit may have a comparatively low compression ratio.

With respect to this proposed apparatus it should be stated that the low-pressure storage container is comparatively large, which is a disadvantage in particular when hot-gas reciprocating engines are to be accommodated in vehicles. In addition, if there is a sudden demand for more power the compressor coupled to the engine shaft claims a significant part of the power during the entire period of power increase.

It is an object of the present invention to provide an improved hot-gas reciprocating apparatus in which the aforementioned disadvantages are at least greatly reduced.

SUMMARY OF THE INVENTION A hot-gas reciprocating apparatus according to the invention is characterized in that the compressor inlet is connected to a first conduit and via this conduit can selectively be connected either to the working space outlet or to the storage container while the compressor outlet is connected to the second conduit and via this conduit can selectively be connected either to the working space inlet or to the storage container.

This provides a construction in which a storage container of medium size and a compressor having an acceptable pressure ratio can be used while a sudden demand for more power can largely be met immediately.

An embodiment of the invention will now be described by way of example with reference to the accompanying diagrammatic drawings:

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE PREFERRED- EMBODIMENT Referring now to FIG. 1, reference numeral 1 denotes a cylinder of a hot-gas reciprocating engine. In this cylinder a piston 2 and a displacer 3 are reciprocable with a relative phase difference. The piston and the displacer are coupled to a driving means, not shown. The piston 2 and the lower surface of the displacer 3 vary the volume of a compression space 4; the displacer 3 by its upper surface varies the volume of an expansion space 5. These two spaces communicate with one another via a cooler 6, a regenerator 7 and a heater 8. A burner 9 supplies heat to the heater 8.

The compression space 4 and the expansion space 5 together constitute the working space of the hot-gas reciprocating engine, with a device 10 for controlling the amount by weight of working fluid in this working space being connected to the engine.

The device 10 comprises a storage container 11 for working fluid and a compressor 12 having an inlet 12a and an outlet 12b. The storage container 11 is connected to an outlet 15 of the working space via a first conduit 13 including a valve 14. The outlet 15 includes a non-return valve 16 which prevents flow of working fluid from the conduit 13 to the compression space 4.

Furthermore the storage container 11 is connected to an inlet 19 of the working space via a second conduit 17 including a valve 18. The inlet 19 includes a nonreturn valve 20 which opens towards the working space. The compressor inlet 12a is connected via the valve 14 to the first conduit 13 and can be connected via this valve and this conduit either to the working space outlet 15 or to the storage container 11. The compressor outlet 12b is connected via the valve 18 to the second conduit 17 and can be connected via this valve and this conduit either to the working space inlet 19 or to the storage container 11.

In constant-power operation of the engine the parts of the conduits l3 and 17 which adjoin the working space are closed by the valves 14 and 18 respectively, as is shown in FIG. 1. Because of the non-return valve 16, there prevails in the said part of the conduit 13 a pressure which is at least substantially equal to the maximum pressure which is produced in the variablepressure working space, while because of the nonreturn valve 20 there prevails in the said part of the conduit 17 a pressure which is at least substantially equal to the minimum pressure produced in the working space.

When working fluid is to be supplied to the compression space 4 in order to increase the power output of the engine the valve 18 is set to the position shown in FIG. 2a. Working fluid then flows from the storage container through the conduit 17 and the non-return valve 20 directly to the compression space 4. At the instant at which the pressures in the storage container 11 and the conduit 17 have become equal the valves 14 and 18 are set to the position shown in FIG. 2b. The compressor 12 then sucks working fluid from the storage container 11 via the valve 14 and presses it into the com pression space 4 via the valve 18 and the conduit 17.

For supplying working fluid in the initial stage, as an alternative the path shown in FIG. 2b may be used instead of that shown in FIG. 2a.

If the power-output of the engine is to be reduced, the valves 14 and 18 are set to the positions shown in FIG. 2c. Working fluid from the motor then flows to the storage container 11 via the non-return valve 16, the conduit 13 and the valve 14. When the pressure in the storage container 11 has become equal to that in the conduit 13 the valves are set to the positions shown in FIG. 2d. Thus the compressor 12 will suck working fluid from the conduit 13 and the compression space 4 to press it into the storage container 11 via the valve 18. If desired the pressures in the storagecontainer 11 and the conduit 13 may be equalized via the path shown in FIG. 2d instead of the path shown in FIG. 2c.

The construction described permits the use of a storage container of medium pressure and a compressor of medium pressure ratio. A sudden demand for power increase may rapidly be met because in the first in- 1. In a hot gas apparatus including reciprocating compression and displacer pistons defining a variablevolume working space for working fluid, the improvement in combination therewith of a device for controlling the amount by weight of working fluid in said working space, comprising: a storage container for containing a quantity of said working fluid, a compressor for said fluid including inlet and outlet means thereof, one-way inlet and outlet valves operable with said working space, a first conduit for communicating said fluid between a first set of three elements, namely said working space outlet valve, said compressor inlet and said storage container, third valve means for selectively inter-connecting two of said three elements, a second conduit for communicating said fluid between a second set of three elements, namely said working space inlet valve, said compressor outlet, and said storage container, and fourth valve means for selectively interconnecting two of said three elements of said second set, whereby fluid can be transferred to said compressor inlet from either the working space outlet valve or the storage container, and from the compressor outlet to either the storage container or the working space inlet valve.

2. In a hot gas engine including reciprocating compression and displacer pistons defining a variablevolume working space for working fluid, the improvement in combination therewith of a device for controlling the amount by weight of working fluid in said working space, comprising: a storage container for containing a quantity of said working fluid, a compressor for said fluid including inlet and outlet means thereof, one-way inlet and outlet valves operable with said working space, a first conduit for communicating said fluid between a first set of three elements, namely said working space outlet valve, said compressor inlet and said storage container, third valve means for selectively inter-connecting two of said three elements, a second conduit for communicating said fluid between a second set of three elements, namely said working space inlet valve, said compressor outlet, and said storage container, and fourth valve means for selectively interconnecting two of said three elements of said second set, whereby fluid can be transferred to said compressor inlet from either the working space outlet valve or the storage container, and from the compressor outlet to either the storage container or the working space inlet valve.

3. Apparatus according to claim 2 wherein said working space comprises compression and expansion spaces, and said inlet and outlet valves communicate with said compression space. 

1. In a hot gas apparatus including reciprocating compression and displacer pistons defining a variable-volume working space for working fluid, the improvement in combination therewith of a device for controlling the amount by weight of working fluid in said working space, comprising: a storage container for containing a quantity of said working fluid, a compressor for said fluid including inlet and outlet means thereof, one-way inlet and outlet valves operable with said working space, a first conduit for communicating said fluid between a first set of three elements, namely said working space outlet valve, said compressor inlet and said storage container, third valve means for selectively inter-connecting two of said three elements, a second conduit for communicating said fluid between a second set of three elements, namely said working space inlet valve, said compressor outlet, and said storage container, and fourth valve means for selectively inter-connecting two of said three elements of said second set, whereby fluid can be transferred to said compressor inlet from either the working space outlet valve or the storage container, and from the compressor outlet to either the storage container or the working space inlet valve.
 2. In a hot gas engine including reciprocating compression and displacer pistons defining a variable-volume working space for working fluid, the improvement in combination therewith of a device for controlling the amount by weight of working fluid in said working space, comprising: a storage container for containing a quantity of said working fluid, a compressor for said fluid includIng inlet and outlet means thereof, one-way inlet and outlet valves operable with said working space, a first conduit for communicating said fluid between a first set of three elements, namely said working space outlet valve, said compressor inlet and said storage container, third valve means for selectively inter-connecting two of said three elements, a second conduit for communicating said fluid between a second set of three elements, namely said working space inlet valve, said compressor outlet, and said storage container, and fourth valve means for selectively interconnecting two of said three elements of said second set, whereby fluid can be transferred to said compressor inlet from either the working space outlet valve or the storage container, and from the compressor outlet to either the storage container or the working space inlet valve.
 3. Apparatus according to claim 2 wherein said working space comprises compression and expansion spaces, and said inlet and outlet valves communicate with said compression space. 